Conflicting reports are emerging since CNN's initial claim that authorities have identified and arrested a suspect believed to be responsible for the Boston Marathon bombings on Monday.

An hour after the cable news network's first report of the arrest, a former FBI agent told CNN on the air that three sources insist no suspect has been identified by name or is in custody.

NBC is reporting multiple sources who confirm no arrest, while Fox News is still sticking to a federal confirmation that an arrest has been made.

More to come...

PREVIOUSLY:

Authorities investigating the Boston Marathon bombings on Monday have arrested a suspect, thanks in part to analysis of a video from a department store near the site of the second explosion and a video from a Boston television station.

CNN reported the breakthrough on Wednesday, citing a source who has been briefed on the investigation. The network also said a press conference has been set for 2 p.m. PT with law-enforcement officials.

Fox News is joining CNN in saying that the suspect -- described as a "brown-skinned male" --has, in fact, been arrested. Other media outlets, however, are reporting that no actual arrest has been made but that a suspect was identified wearing a backpack believed to be carrying one of the bombs. The Associated Press would only say a suspect was "in custody."

CNN also is reporting that a federal-law enforcement source said a lid to a pressure cooker thought to have been used in the bombings had been found on a roof of a building near the scene.

The surveillance footage was from upscale clothing retailer Lord & Taylor, but CNN's source declined to specify what media outlet the television footage came from.

Prior to the suspect's arrest, investigators still didn't know whether the attack was an act of foreign or domestic terrorism.

"If your experience and your expertise is Middle East terrorism, it has the hallmarks of al Qaeda or a Middle East group," former FBI Assistant Director Tom Fuentes told CNN. "If your experience is domestic groups and bombings that have occurred here, it has the hallmarks of a domestic terrorist like Eric Rudolph in the 1996 Atlanta Summer Olympics bombings."

Two bombs exploded 12 seconds apart during the Boston Marathon on Monday. The blasts killed three people and wounded 183 others, according to most recent reports.
The FBI says at least one of the bombs was housed in a pressure cooker hidden inside a backpack, while the second bomb was also housed in a metal container, but it was not clear whether it too was in a pressure cooker.

Various forms of media played a huge part in this case. Before identifying the suspect seen in the two videos, authorities were sifting through more than 2,000 tips, a mass of digital photos and video clips.